This includes not just isolated cases of oral clefts, but also additional congenital malformations.
When cases of additional malformations are excluded, the infant mortality rate for those with only an oral cleft is two times that of the overall population.
The claims come after a meta-analysis of published research, which spans nearly the past 70 years.
This study was conducted to form a more comprehensive assessment of the high infant mortality rate.
The authors examined literature published from 1943 to 2010, analysing infant mortality related to oral clefts.
But infant mortality due to congenital malformations has continued to increase during the past seven decades.
Cleft lip and/or palate is one of the most common anomalies, affecting about 1 in 700 infants.
The studies analysed were all from developed countries with a high standard of health, possibly creating a better outlook than actually exists, the author said.
Some studies have shown a connection between oral clefts and low birth weight, which is also a risk factor for infant mortality.
Another factor that may cloud the results is an unknown rate of pregnancy termination for fetuses diagnosed with malformations.
The paper has been published in Cleft Palate–Craniofacial Journal
and can be viewed here